Solve Et Coagula
by define-serenity
Summary: [Barry/Caitlin] After receiving a P on his Potions O.W.L. Professor Zolomon insisted he got a tutor before repeating the test later that fall, and since Caitlin was one of the few around here working towards becoming a career Potioneer, perhaps even an Alchemist, he had to try and get her help.


**author's notes:** written for **Snowbarry Week 2017** , day 1: **Hogwarts/magic au**.

 _._

 **Solve Et Coagula**

.

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 _Solve et coagula;_

 _for something to be built,_

 _it must first be broken down._

 _._

A small group of large snow owls soars through the open windows of the Great Hall, diving down to drop packages into their respective owners' laps, before returning to the owlery in the West Tower. Students pour in for a late breakfast before classes start, copying homework at the last minute, catching up on the latest gossip from the other houses, or reading through the mail.

To Barry's left, Iris' quill scratches lightning fast at a piece of parchment, while to his right, Cisco sits reading through his Herbology summaries, going over the material one last time before the test later this morning.

"Hey, Flash!" a voice carries like an echo through the room, and he looks up in time to watch a small package being flung his way by Patty Spivot, one of Hufflepuff's best Chasers. "Catch!"

He catches the package mid-air and settles down between his two best friends again, checking the brown paper for any markings; there are none.

Cisco mumbles, "Flash. Like that handle's going to stick."

" _Hey_ ," Iris interjects, defending the nickname like always; it was her contribution to his illustrious Quidditch career these past few years, and she's taken a great amount of pride detailing his daring exploits as Gryffindor's star Seeker.

Unlike most other Seventh Years she ambitioned a career at the Daily Prophet, and has so far done everything within her power to achieve those goals. She started a Hogwarts newsletter that appeared each month, and recruited writers from each House to contribute their stories. This month's would be dedicated to S.P.E.W., the Society for the Promotion of Elfish Welfare, founded by Linda Park and Brie Larvan one late night in the library.

"I like the name," he says, untying the rope around his package. "It's better than The Boy Who Lived."

"Honestly" -Cisco rolls his eyes- "you get struck by lightning once."

He laughs, even though he remembers little of that day beyond the start of the game in the worst of a thunderstorm; everyone wore goggles spelled to repel the rain, but no one counted on the lightning to strike him down in the middle of his pursuit of the Golden Snitch. His beloved Nimbus broomstick burnt to a crisp and, according to all the stories, he'd frozen from the impact of the lightning and fell like a clump to the ground. He might've broken every bone in his body had Professor Wells' _Arresto Momentum_ spell not slowed him down mid-air.

Someone at the school -he suspects it may have been Cisco- started calling him The Boy Who Lived and it caught on quickly, ending up on buttons and T-shirts he gathers sold for a Galleon or two - it'd always struck him as suspicious how Cisco got him a sweater that Christmas rather than the standard new pair of socks.

Thankfully, with Iris on his side and 'the Boy who Lived' taking up too much space on her newsletters, she'd come up with a far more tolerable name. _The Flash_ suited him; he was one of the fastest players, after all.

He loosens the jute twine around the package and unearths a Remembrall, a large marble sized glass ball containing smoke; this one, now laying in the palm of his hand, quickly fills with red smoke, which tells him one thing. He forgot something important. Which wouldn't be the first time.

"I hate those things," Cisco sighs, but fails to hide his amusement at the sight of the smoke. "How does that help you remember anything?"

"My Potions essay," he hushes, and jerks upright as the smoke in the Remembrall turns white. The twelve inches of parchment were due this morning, and it's still upstairs in the Common Room.

Iris raises an eyebrow. "She's making you write essays now?"

" _Caitlin_ " -he stresses, painfully reminded why he and Caitlin decided to keep things low-key- "helped me pass three Potions tests in a row."

No one can argue with those results.

He grabs another piece of toast and leaves the table, all but running for the Great Hall's double doors; he has to climb seven floors to reach the Gryffindor Common Room and remember the new password and he barely has twenty minutes to make Caitlin's deadline. Why was he so forgetful all the time?

After receiving a P on his Potions O.W.L. Professor Zolomon insisted he got a tutor before repeating the test later that fall, and since Caitlin was one of the few around here working towards becoming a career Potioneer, perhaps even an Alchemist, he had to try and get her help. For a brief moment he'd considered asking Hartley, fast on his way to achieving all twelve N.E.W.T.S, but something told him that despite being from a rival house, Caitlin would be far more amenable to his request.

He was right.

Under Caitlin's studious tutelage he'd made great strides in mastering Potions; she taught him patience and care in preparing his ingredients, tricks to remember which ingredients were used in the more basic potions, and to always, without fail, scrub down his work station, weighing scales and glass phials he reused, lest older materials transferred to any fresh potions he worked on. Only the experienced masters could teach him the intricacies of timing, ageing and stirring techniques, but Caitlin gleaned her fair share of knowledge having sat through Professor Zolomon's advanced class and doing a lot of additional reading.

After several months of working together he now knew the types of cauldrons and vials, the twelve uses of dragon's blood, and could tell the difference between Monkshood and Wolfsbane. A few weeks from now he'd be sitting his second Potions O.W.L. in the hopes of achieving his N.E.W.T. at the end of the year, and he'd never felt more ready.

"You're late," Caitlin calls over her shoulder as he locates her in the library, tucked in between cases on Muggle history and heavy volumes filled with star charts. Early morning sun filters in through the Tudor windows, letting in a soft breeze to chase away the dusty smell of old books.

He breathes hard, "I know, I'm sorry", his calves burning from exercise he's not used to, and quickly slips his essay under Caitlin's nose, as if that somehow made up for the time. Her robes are thrown over the back of her chair, the gray sleeves of her sweater rolled up over her elbows, her green striped tie loosened a little around her neck. She's a vision, like always, taking his breath away.

"Remembrall was a nice touch," he says, drawing a hand along her shoulders.

"I can't have you wasting my time, Barry Allen," Caitlin quips, while a fond smile curls around her lips, and his heart skips that natural beat he can't ascribe to any kind of exercise. Wasn't it that long ago he avoided Slytherins at all costs?

Leaning in, he brushes their lips together, and feels a short sweet kiss pushed back against his mouth; a flutter rushes up his spine, along with a safety and security he's scarcely felt in his entire life. Months of tutoring had brought him and Caitlin closer together, as friends, as wizards, as people who'd held onto prejudices started by some old people who founded the school. Slytherins and Gryffindors may not share all of the same qualities, but behind the pride and bravery, the smarts and cunning, chivalry and resourcefulness, none of them were all that different.

Besides her beauty Caitlin proved wickedly smart, especially when it came to more theoretical and academic things; he, in turn, was better at the practicalities of magic, like flying and casting spells. He thought this made them a perfect pair, each holding what the other needed, Caitlin's care, kindness and punctuality a perfect counterpart to his daring friendly and tardy disposition. Maybe that's what the Houses were really for; cultivating minds that could, in time, complement each other.

"Are you nervous?" Caitlin whispers to his lips.

"A little." He bites at the inside of his cheek, and sits down next to her, leaning down on one arm. Today's meant to conclude his skilled tutoring, with one final essay to prove he's ready to retake his O.W.L. He shrugs, and smiles furtively. "No going back now."

Caitlin shifts forward and begs another kiss, before going to work.

For the next half hour he sits next to Caitlin in complete silence, while she carefully checks over his essay; her quill rests against her mouth and she bites at her lower lip now and then, nib scratching notes into the margins. He tries his best not to squirm, not to tap his foot or drum his fingers onto the wooden desk, but the suspense is killing him. He needed a minimum of five N.E.W.T.S. if he wanted to start training as an Auror, and a good mark on his Potions final will prove vital to his applications.

He should've found a tutor a long time ago. School never came easy to him, not before Hogwarts or at Hogwarts; he's easily distracted, by Cisco's or Wally's schemes to one-up Slytherin in the race for the House Cup, or anything that simply sounded more fun than sitting locked up in the Common Room poring through his books - and his grades had suffered. That hadn't mattered until it did, until it became clear that his previous lot in life didn't have to persist after finishing school.

First, Iris made him realize there could be a future for him as an Auror, that his life in the magic community didn't have to end after his Seventh Year, and he didn't have to return to a Muggle life that'd made him miserable. He had a calling and a purpose and while Year Four was a late time to have that epiphany, he'd started working towards that future. Sadly, academics weren't a talent of his. It took another two years and a P on his O.W.L. for him to seek out additional help.

Caitlin helped him find focus and logic through the muck of words in his textbooks, and stilled some of the chaos that'd thus far kept his heart and mind prisoner. And through all that she'd become someone different to him still - not just a tutor, but someone who believed in him, someone he could open up to, and someone who could be more than the smartest girl in the room around him.

At long last, Caitlin replaces her quill in the small inkwell sat between them, and looks at him. His heart rate picks up again and all of a sudden his _need_ for this claws at him from every angle; he's worked so hard for this and he's come so far - it'd be a shame if it turned out to be for nothing.

But then, a proud smile settles along Caitlin's mouth, and she blinks slowly. "I think you're ready."

His eyebrows rise. "Yeah?"

"Your grammar needs work," Caitlin teases, and turns to face him, "but you'll pass your Potions O.W.L. without breaking a sweat."

The breath he'd held pops free and his veins fill with the true meaning of this; everything he ever wanted is within arm's reach, it's more than he's ever had, and he owes it all to Caitlin taking a chance on a distracted Gryffindor who'd much rather have spent his time outdoors when they first started their lessons.

"Cait," he hushes, overcome with an elation that spreads to all his limbs at once, "you have no idea what this means to me."

After all this time, after all these years, he might be able to make peace with what the Dark Arts took from him; he could avenge his mom's death and his dad's insanity by helping others, by stopping evil witches and wizards from destroying other families they deemed impure simply because one of them was a Muggle. His dad never hurt anyone in his life and yet he paid for his kindness towards others; and his mom, God, his mom, she'd given her life to protect them both.

"Hey." Caitlin's hand slips over his. "They would be so proud of you."

He can't know what his parents would've wanted for him; he barely remembers his mom's face and his dad hasn't spoken a sensible word in over fourteen years, but he likes to think their hopes for him included Hogwarts, friends for life like Iris and Cisco, and someone who loved him as much as Caitlin does.

"Is it weird that-" he says, but a smile gets in the way; in no future had he imagined falling head over heels for a Slytherin, or that falling in love could feel so complete and overwhelming. If he could he'd spend every waking moment he had with Caitlin, and he wouldn't care if the whole school knew.

At first, maybe it'd been embarrassment that kept him from telling anyone; Slytherins weren't just Gryffindor's greatest rivals in Quidditch but in competing for the House Cup too, and both sides had taken action to undo the other's hard work through tricks and deception, and one jinx that'd gone horribly awry in one of the girls' bathrooms.

Then, Caitlin spoke of her difficult relationship with her mother, and how even though the Snow matriarch wanted nothing but happiness for her daughter, she was also intent on safeguarding the bloodline - Caitlin didn't care, nor did she desire to fall in love with pure-bloods simply because her mother decreed it, but it had destroyed her last relationship, and for now, for a while longer, she wanted Barry all to herself.

It'd been a difficult conversation, one that'd led to a week's radio silence between them before he told Caitlin what'd happened to his parents; she'd cried for him and the things he lost, and apologized for bringing it all up again, even though he carried it with him every day of his life.

It was the first time she'd told him about Ronnie Raymond, a Muggle-born wizard Caitlin met during her summers in Godric's Hollow, where the two had fallen in love. For three consecutive summers she'd felt like the luckiest girl in the world, until Ronnie disappeared; no more letters came, hers came back unopened, and any questions she had remained unanswered until she'd run into him at Diagon Alley. That's where she found out the terrible truth; how her mother threatened Ronnie and his family if he didn't break all contact, how the Snow bloodline could not be tainted with -Caitlin choked out the word- muddled blood.

All along she thought Ronnie broke her heart but truth was her mother bore responsibility.

So they'd agreed to keep their relationship a secret, to avoid more rivalry among their houses, to postpone a conversation they'd undoubtedly be coming back to. For a little while longer, he'd keep Caitlin to himself, and she'd keep him to herself, and that was good enough.

Now, with Caitlin right there, he can't think of a single reason why they should keep hiding. It's not like anyone judged Eddie for being a Hufflepuff when he and Iris started dating, and no one looked twice at Cisco and Gypsy.

"What?" Caitlin insists, and stands, settling down in his lap with her arms thrown around his neck - it doesn't matter to him which House Caitlin's from; seven years was a long time to realize the Sorting Hat perhaps knew what it was doing, but it still created unnecessary rifts between people who might've otherwise been friends. He's grateful growing older -and a little bit wiser- made a lot of people see past all that.

He chuckles shyly. "I feel like I won the lottery."

Caitlin's lips twitch uncomfortably, like they often do when she doesn't understand something, and her eyes narrow on his face. "What's the lottery?"

He laughs.

"Don't laugh!" She pokes a finger at his chest, her nose scrunching. "Is it a Muggle thing?"

His fondness curls around his heart like a warm blanket. "Yeah." He nods, brushing a lock of Caitlin's hair back behind her ear. "It just means I feel like a very lucky guy."

Caitlin pulls him closer. "And I'm a very lucky girl," she says, and pushes their lips together again.

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 **fin**

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End file.
